Despite storms, December weather was dry
By: Scott Mobley

A man walks south on Market Street over the Sacramento River on Christmas Eve. Redding Municipal Airport notched a record low on Dec. 18, when the mercury hit 23 degrees.

2008 weather highlights

The following observations were taken at the Redding Municipal Airport:

Greatest 24-hour precipitation total: 1.95 inches, Jan. 4.

Highest wind gust: 82 mph, Jan. 4.

Highest temperature: 113 degrees, July 9.

Lowest temperature: 23 degrees, Dec. 18.

Total precipitation: 21.70 inches.

Annual average precipitation: 33.52 inches.

December felt a little like a bad romance. It started off buttered-popcorn warm - and then turned just plain old cold.

The chill that arrived Dec. 13 abruptly ended weeks of dry, unseasonably mild weather. Waves of polar air set multiple low temperature records from Burney to Redding and brought mounds of powdery snow to the foothills and mountains that soon turned to ice.

The cold spell even left a thin coat of snow on hoods and lawns around the far northern Sacramento Valley floor the morning of Dec. 15.

But these Arctic storms did little to ease California's increasingly critical water shortage. Precipitation was sub-par in most north state spots for an 11th straight month, making 2008 even drier than 2007, already one of the driest in recent memory.

And there's little sign January will deliver a much needed deluge to Northern California, longer-range forecasts indicate.

A cold front expected to sweep the state this evening into Friday morning could leave up to a half-inch of rain on the valley floor and maybe a half-foot of snow on the higher mountains slopes. But there's no other significant rain on the horizon out toward mid-month once that front passes.

December's weather was the story of the bulbous high pressure ridge that has sat like a hen over California during these past two years of drought.

The ridge anchored off the West Coast the first 12 days of December, blocking any storms that might have struck the north state. Afternoon temperatures wafted to a vernal 72 degrees in Red Bluff, tying a record high for the date set in 1976.

But then the hemispheric circulation rearranged itself, with huge consequences on the ground.

The ridge migrated west and bulged into interior Alaska, allowing polar air to rush down through the Yukon and pool over the Pacific Northwest and far Northern California. Afternoon temperatures in Redding failed to break 50 degrees on 14 days during the cold spell.

Redding Municipal Airport notched a record low on Dec. 18, when the mercury bottomed out at 23 degrees. The old record of 24 degrees was set in 1924 and matched in 1989, Western Regional Climate Center data shows.

Burney busted record-low temperatures on consecutive days last month during the depth of the cold spell. The first record fell Dec. 17, when the temperature dropped to minus 8 degrees. The mercury in Burney hit minus 5 degrees early on Dec. 18, glazing the old record of 1 degree set in 1948.

Cold air doesn't carry as much moisture as warmer air. So even though December's bone-chilling blasts brought plenty of clouds, rain and snow, the precipitation never added up to much.

Shasta Dam recorded 3.76 inches of precipitation last month. That's a mere 34 percent of the 10.99 the dam soaks up in a typical December.

Other below-average north state December precipitation totals include 6 inches in Shingletown, 4.30 inches in the Summit City area of Shasta Lake, 3.28 inches in west Redding, 3.04 inches in Enterprise, 1.65 inches in Red Bluff and 1.61 inches in Mount Shasta.

Lake Shasta rose to 151.74 feet of the dam crest, thanks to trickling inflow from rain and melting snow in the surrounding mountains. Still, the lake hovers close to its lowest level since the historic 1977 drought.